Incompressible fluid type rock breaker

ABSTRACT

A rock breaker comprising a tool insertable in a hole in a rock and fed through a supply line with an incompressible liquid to maintain a column of the liquid in the hole, and means to apply to the liquid a shock means sufficiently high to fracture the rock, the tool comprising a hollow stem having an expansible collet and a resilient sealing ring and mechanical means to expand the collet and ring.

FIELD OF THE INVENTION

This invention relates to an improved rock breaker and in particular itrelates to a breaker of a type which uses pressure fluid to fracturerocks or similar fracturable materials.

BACKGROUND OF THE INVENTION

The reason why various forms of apparatus have been suggested forfracturing rocks is to be able to provide a means which, unlike anexplosive, will cause fracture but will not cause the material to beprojected from the site. Amongst earlier attempts to fracture materialsin this way reference can be had to U.S. Pat. No. 4,123,108 in the nameof Eric V. Lavon in which a material such as rock is broken by forcing alongish mass body of relatively incompressible fluid, such as water,against the material to be broken, or U.S. Pat. No. 4,141,592 also inthe name of Eric V. Lavon in which the rock is broken by maintaining acolumn of relatively incompressible fluid in a tube the inner end ofwhich is inserted in a predrilled hole in the rock and then generatingpressure in the column by means of a piston applied to the tube outsideof the hole, which pressure is transmitted through the column to thefluid in the hole.

It has also been proposed in Australian Pat. No. 163,489, ImperialChemical Industries Limited, to fill a hole drilled into rock or thelike with an incompressible liquid and to then use an explosive toprovide a shock wave in the material.

Reference is also to be had to Australian Pat. No. 500,571 filed bymyself on the 3rd December, 1974 which was designed specifically to usea fracture method in which a shock wave was applied to an incompressibleliquid sealed in a hole drilled into a rock or the like which is to bebroken. An object of that invention was to achieve safety by preventingthe force generated to fracture the rock from hurling fragments of therock for a considerable distance as is the case in blasting or the like,and this object was achieved by providing apparatus which can be sealedinto the hole sufficiently securely to avoid ejection of the device whenthe shock is applied and at the same time to cause fracture by the shockapplied to the rock or other fracturable material. That earlier deviceutilized a tool which was both anchored in a hole drilled in the rock orthe like and which was provided which sealing means to prevent egress offluid placed under pressure in the hole.

It was known prior to my earlier invention referred to above to use atool which could be sealed in a hole drilled in the materials to befractured and reference can be had to U.S. Pat. No. 2,840,360 in thename of Jean Jerusel which utilized a series of expansible resilientrings between sections of the tool and the wall of the hole to preventhigh pressure liquid such as water injected into the hole for miningpurposes from leaking from the hole, but my earlier invention variedfrom this by using both a split collet and resilient sealing means, thesplit collet being expanded in the rock to prevent withdrawal of thetool and the resilient sealing means being compressed to form a tightjunction with the wall of the hole to ensure that liquids cannot bypassthe tool.

In my invention both of these members were hydraulically actuated in anindependent manner and while satisfactory for the purpose it is theobject of the present invention to provide an improved form of tool ofsimple construction which can be readily inserted into a hole drilledinto a rock or fracturable member, which can then be locked therein tocompletely seal the hole, and which can readily be released after use,the present invention avoiding the need to use pressure fluid to actuatethe holding collet and the liquid seal.

The device according to this invention thus comprises a tool which isadapted to be connected to a liquid pressure supply firstly to fill ahole in which the tool is inserted and secondly to apply the necessaryhigh pressure shock to the fluid to fracture the rock, the toolcomprising a hollow stem with a tapered section at its remote end andmeans at the other end to connect the liquid supply, the hollow stemhaving on it a collet which is split so that it can be expanded whenrelative movement between the stem and the collet takes place, thepressure to expand the collet being obtained by using a member whichengages a thread on the stem and draws the stem upwardly in relation tothe collet, a sleeve extending from the top of the collet around thestem to be engaged by the thread operated means to hold the collet inposition when the stem is moved upwardly in the sleeve.

The stem is also encircled by a resilient sealing member which is soarranged that it can be compressed either by being positioned betweenthe collet and the aforesaid sleeve or it can be compressedindependently by a further sleeve encircling the first sleeve andprovided with means such as a screw thread on the first sleeve and a nutengaging the second sleeve to allow the seal to be compressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a unit constructed according to theinvention showing a portable power unit for filling the hole with waterand for providing the necessary shock to cause fracture of the rock, thetool being shown connected to the power unit so that this tool can beinserted in a hole drilled in a rock which is to be fractured.

FIG. 2 is a perspective view of the power unit from a different angle.

FIG. 3 is a schematic view showing how the power unit is connected tothe liquid supply, showing also the accumulator and mechanism forsupplying the shock force.

FIG. 4 is a view of the simplest form of the tool showing the parts in aposition where the tool is ready to be inserted into a hole drilled inthe rock or like fracturable material.

FIG. 5 shows the tool actually inserted into the rock with the collettightened and the seal expanded in readiness to apply the liquid to thehole.

FIG. 6 is a view of a modified form in which expansion of the collet andexpansion of the seal are effected independently instead of by means ofa single adjustment member as shown more particularly in FIGS. 4 and 5.

PREFERRED CONSTRUCTION

Referring first to the tool which is inserted into the hole in the rockor like fracturable material which is to be split, this comprises ahollow stem 1 having at its top a screw threaded portion 2 and at itsother end, which is the lower end when inserted into a hole, a taperedportion 3 which has a flange 4 at its end, and this stem carries on itthe split collet 5 which is formed in two halves held together bycirclips 6 and 7 one at each end of the collet, the collet having on ita series of saw-tooth ridges 8 which can be forced tightly against therock to ensure that the collet cannot be dislodged outwardly whenpressure exists within the hole.

The hollow stem 1 is moved upwards in relation to the collet 5 when itis desired to expand the collet. This is achieved by manipulating ahandle 10 which has on it a nut 11 which engages the threaded portion 2of the stem 1, through a ratchet 12 and disposed between the nut 11 andthe top of collet 5 are a series of members, the first being anantifriction ring 13 engaging a sleeve 14 which at its lower end engagesthe upper edge of an expansible sealing member 15, the lower end of thesealing member 15 being engaged by a spacer 16 which rests on the top ofthe collet 5, the assembly being such that when the nut 11 is rotated onthe stem 1, the assembly between it and the collet 5 applies acompressive force on the sealing member 15 to force the material intotight contact with the wall of the hole in which the tool is positioned,at the same time forming a restriction against upward movement of thecollet so that as the stem 1 is drawn upward by the nut 11 moving on thescrew threaded portion 2, the collet 5 is expanded to firmly engage thewall of the hole due to the tapered portion 3 of the stem moving intothe collet to urge the two parts thereof outwardly.

A spring 17 encircles the lower part of the stem 1 between the flange 4and the bottom of the collet 5 so that, when it is desired to remove thedevice from the hole, the stem 1 will be drawn downwards by the spring17 to collapse the collet 5 and at the same time, because the pressureis removed which was applied to the sealing member 15, allowing thesealing member to return to its unexpanded form to release the tool fromthe hole. The hollow of the stem is designated 18 and extends axiallyright through the stem to open into a connector 19 at the top of thestem.

According to the modification shown in FIG. 6, the main stem 20 has atits lower end a tapered section 21 encircled by a split collet 22 soarranged that the collet 22 can be expanded to firmly lock the rockbreaker in a hole by pulling the main stem 20 upwardly while leaving thecollet 22 in position, the main stem 20 in turn being encircled by asleeve 23 which engages the top of the collet 22 and the upper end ofwhich is encircled by a further sleeve 24 which fits around the firstsleeve 23 and extends to near the top of it. The first sleeve 23 has onit between the sleeve 24 and an expanded part 25 at its lower end aresilient sealing ring 26, the expanded end 25 of the first sleeve 23engaging the top of the split collet 22.

The compression of the sealing ring 26 is effected by forcing it on tothe expanded portion 25 of the first sleeve 23 by means of the sleeve 24which encircles the secondary stem 25.

The main stem 20 has at its top a screw threaded section 28 which isengaged by a collet tightening nut 29 and this nut 29 bears on the firstsleeve 23 which in turn engages and holds the collet 22 in place whenthe collet tightening nut 29 is manipulated to force the main stem 20upwardly by reaction against the first sleeve 23, to thereby expand thecollet by means of a tapered lower section 21 of the stem 20 to lock thecollet firmly in position in the hole in the rock. The collet tighteningnut 29 is rotated through a ratchet 30 by a handle 31.

The split collet 22 again has a number of sawtooth ridges 33 around itso arranged that they bite into the rock face when the pressure isexerted to prevent the collet from being moved upwardly and to therebyfirmly lock the rock breaker in position against ejection from the holewhen the pressure is applied. The split collet is held together bycirclips 34 and 35.

To compress the sealing ring 25, a seal tightening nut 36 engages athreaded portion 32 on the upper part of the first sleeve 23 so thatwhen the nut 36 is wound downwardly to force the sleeve 24 down on tothe sealing ring 25, this sealing ring 26 is compressed to form aneffective high pressure seal at this locality.

The nut 36 is rotated through a ratchet 37 by a second lever 38.

This assembly results in a simple arrangement which merely requires asplit collet 22 to be assembled on the main stem 20 in contact with atapered section 21 thereof and to then place the first sleeve 24 intoposition, which engages the top of the collet 22, which in turn engagesthe collet tightening nut 29 so that when this nut is manipulated thecollet will engage firmly on the rock but this action does notnecessarily affect the position of the sealing ring 26 which in turn isplaced over the first sleeve 24 which has at its upper end the threadedportion 32 and is engaged by the seal tightening nut 36 so that the nut36 forces the sleeve 24 down on the first sleeve 23 to firmly compressthe sealing ring 26.

In this way, by simply manipulating the collet tightening nut 29 throughthe lever 31, and then the seal tightening nut 36 when the device hasbeen assembled in a hole, the device is locked against ejection by theexpanded split collet 22 and when the nut 36 is screwed down liquid isprevented from being lost from the hole by the sealing ring 26 engagingthe wall of the hole in the rock to prevent leakage from beneath thetool.

A junction 39 is again positioned at the top of the hollow stem 20 toallow a column of water to be supplied to the hollow stem. In both ofthe forms of the tool described above, the tool is inserted in a borehole 40 in a rock 41 or other member to be fractured, and when highpressure liquid is applied, the rock will be fractured.

The mechanism for applying the operating pressure to the tool is shownmounted on a frame 42 mounted on wheels 43 and provided with handles 44to allow the unit to be conveyed.

The mechanism for applying the pressure comprises a water line 50 whichleads through a flow control valve 51 to a line 52 which in turn joinsto the junction 19 or 39 of the tool to allow a flow to take place intothe bottom of the hole 40 in the rock 41, a check valve 53 beingincluded in the line as well as the control valve 51.

Water also flows through a filter 54 through a check valve 55 to thehigh pressure cylinder 56 of an intensifier 57 and from this through acheck valve 58 and line 59 to an accumulator 60 which has in it a gasfilled bag in usual manner. Pressure water from the accumulator 60passes through a quick release trigger valve 61 which is arranged toallow a sudden flow of water through this valve when it is opened, waterflowing from the valve 61 through the line 62 to the junction on thehollow stem to apply water pressure to the hole.

A bleed valve 64 allows the line 62 up to the trigger valve 61 to befilled with water so that when initially filling the hole 40 with waterthe column of water extends from the hole right up to the valve 61 sothat when the valve is open, pressure from the accumulator 60 issuddenly released to place a shock loading on to the water in thepressure line 62 and the water within the hole 40, back-flow along theline 52 being prevented by the one-way valve 53.

The intensifier can be of usual type and is shown as air-operated, airflowing through the line 65 and valve 66 to a water trap 67, a regulatorvalve 68 and a lubricator 69 the air then passing through the line 70into the large cylinder 71 of the intensifier 57 to operate a largepiston in cylinder 71 of the intensifier to in turn actuate a smallpiston in the cylinder 53 in the intensifier whereby to provide the highpressure water for effecting a fracture. Air from the intensifier isexhausted through the muffler 72. Intensifiers and their onstructionsare well known in the art.

I claim:
 1. A rock breaker for fracturing rock or other fracturablematerial comprising:a portable frame having on its means to receiveliquid from a source of supply, a pressure intensifier on the said frameconnected to the said liquid supply, and accumulator also on said frameconnected to said intensifier to compress a gas in the said accumulatorwhen liquid under pressure is fed from the said intensifier to the saidaccumulator, a tool insertable in a hole in the said rock or fracturablematerial, a flexible high-pressure line connecting the said accumulatorwith the said tool, means to bleed air from the said line, a quickrelease valve in the said high-pressure line, a further flexiblelower-pressure line placing into communication the said liquid sourceand the said pressure line between the said valve and the said tool, anon-return valve in the said further line at the said pressure line, thesaid tool comprising a hollow stem having at a first end portion meansto engage at least the said pressure line to feed liquid through thesaid hollow stem into the said hole, and actuating means for holding andsealing the said tool in the said hole, said holding and sealing meanscomprising an expansible collet on the said stem at a second portionthereof and a resilient expansible sealing member encircling the saidstem, whereby when in use, the said tool is locked in the said hole whenthe said collet is expanded and said hole is sealed against egress ofliquid therefrom past the said tool when the resilient sealing member isexpanded, and the said hole has a column of liquid maintained in it bysupply from the said further line through the said non-return valve, andthe rock or fracturable material is split when the said liquid has highpressure applied to it from the said accumulator through the said highpressure line and the said tool.
 2. A rock breaker according to claim 1wherein the said tool comprises:a hollow stem having at one end portiona thread and means to allow liquid to be fed through the said hollowstem into the said hole, an expansible collet encircling the said hollowstem toward its other end, a threaded member engaging the said screwthread on the said stem arranged to be moved axially on the said stem,means on the said hollow stem to expand the said collet, when the saidthreaded member is moved on the said thread, a resilient expansiblesealing member encircling the said stem intermediate the said collet andthe said threaded end of the said stem, and means to expand the diameterof the said sealing member by compressing the said sealing member.
 3. Arock breaker for fracturing rock or fracturable material comprising:(a)a tool insertable in a hole in a rock or fracturable material andarranged to be fed through a supply line with an incompressible liquidto maintain a column of the said liquid in the said hole, (b) means tosupply liquid at a pressure sufficiently high to fracture the rock orfracturable material, and to suddenly apply the said high-pressureliquid to the said column of liquid in the said hole to fracture thesaid rock, said tool comprising, (c) a non-rotational hollow stem havingat one end portion a thread and means to allow liquid to be fed throughthe said hollow stem into said hole, (d) an expansible collet encirclinga tapered portion on the said hollow stem at the other end remote fromthe said thread, (e) a threaded driving member engaging the said screwthread on the said stem arranged to be moved axially on the said stemwhen rotated about the said stem, (f) a sleeve on the said hollow stemto move the said collet to expand the said collet when the said threadedmember is moved on the said screw thread, (g) a resilient expansiblesealing member encircling the said stem intermediate the said collet andthe said threaded end of the said stem, and (h) means to expand thediameter of the said sealing member by compressing the said sealingmember.
 4. A rock breaker according to claim 3 wherein the said sleevebetween the said threaded member and the said collet is transverselydivided and has the said resilient sealing member interposed between thetwo parts of the said so divided sleeve, whereby the said threadedmember when moved to expand the said collet through the said sleeve alsocompresses the said resilient sealing member to expand it.
 5. A rockbreaker according to claim 3 wherein the said sleeve extends between thesaid threaded member and the said collet and has an expanded portion atthe said collet and has the other end externally threaded, and the saidresilient sealing member encircles the said sleeve and engages the saidexpanded portion, and by a further sleeve encircling the first saidsleeve to extend between the said resilient sealing member and athreaded member engaged on the said thread on the first said sleevewhereby the said threaded member when moved toward the said resilientsealing member compresses the said resilient sealing member to expand itindependently of movement of the first said sleeve.
 6. A rock breakeraccording to claim 4 or claim 5 wherein the said threaded member, oreach said threaded member, includes an extending operating handle, andincludes a ratchet mechanism between the extending operating handle andthe said threaded member.
 7. A rock breaker according to claim 3 whereinthe said hollow stem has an outwardly extending flange at the endopposite the said threaded portion, and a compression spring on the saidstem confined between the said flange and the said collet, and the saidtaper increases progressively in diameter toward the said flange,whereby when the said hollow stem is moved in relation to the saidcollet to expand the said collet the said spring is compressed wherebyto urge the said collet back from the larger diameter of the said taperwhen the said stem is oppositely moved so as to decrease the diameter ofthe said collet.
 8. A rock breaker according to claim 3 wherein the saidhollow tube has a connector at the threaded end to attach a pair ofsupply lines to it, the one supply line being adapted to feed lowpressure liquid into the said hollow stem through a non-return valve tomaintain the said column of liquid in the said hole, and the other saidsupply line being adapted to feed high-pressure liquid to the saidhollow stem through a quick release valve to momentarily apply thehigh-pressure to the said column of liquid in the said hole.
 9. A rockbreaker according to claim 3 wherein the means for supplying liquid tothe said hollow stem comprise, a supply line from a liquid sourceconnected to supply liquid through a non-return valve to the said hollowstem, and a supply line to apply high-pressure liquid to the said hollowstem through a quick release valve from an accumulator, a wheeled frameto support the said accumulator, a pressure intensifier also mounted onsaid wheeled frame and fed from a liquid source, means to cause theintensifier to charge the said accumulator with liquid to compress a gasin a bag in said accumulator to pressurize the liquid sufficiently tofracture the rock or fracturable material.
 10. A rock breaker forfracturing rock or other fracturable material comprising:a portableframe having on it means to receive liquid from a source of supply, apressure intensifier on the said frame connected to the said liquidsupply, an accumulator also on said frame connected to said intensifierto compress a gas in the said accumulator when liquid under pressure isfed from the said intensifier to the said accumulator, a tool insertablein a hole in the said rock or fracturable material, a high-pressure lineconnecting the said accumulator with the said tool, a quick releasevalve in the said high-pressure line, a further line communicating withthe means which receive liquid from the said source and the saidpressure line between the said valve and the said tool, a non-returnvalve in the said further line at the said pressure line, bleed means onsaid high-pressure line to allow air to be expelled from saidhigh-pressure line, said tool comprising a hollow stem having at one endportion a thread and means to engage at least the said pressure line tofeed liquid through the said hollow stem into the said hole, a collet onthe said stem at the other end portion thereof arranged to be expandedby a tapered section of the said stem to lock the said tool in the saidhole, a threaded operating member on the said thread on the said stemconnected by a sleeve on the said stem, which is interposed between thesaid threaded member and the said collet whereby to expand the saidcollet on the said taper when the said operating member is moved in afirst direction, a resilient expansible sealing member encircling thesaid stem, means to expand the said sealing member on the said stem, anda return spring to move the said stem to collapse the said collet andthe said expansible sealing member when the said threaded operatingmember is moved in a direction opposite to the said first direction,whereby the said tool is locked in the said hole when the said collet isexpanded and the said hole is sealed against egress of liquid therefrompast the said tool when the resilient sealing member is expanded, andthe said hole has a column of liquid maintained in it by supply from thesaid further line through the said non-return valve, and the rock orfracturable material is split when the said liquid has high-pressureapplied to it from the said accumulator through the said high-pressureline and the said tool.
 11. A rock breaker according to claim 10 whereinthe said sleeve between the said threaded member and the said collet istransversely divided and has the said resilient sealing memberinterposed between the two parts of the said so divided sleeve, wherebythe said threaded member when moved to expand the said collet throughthe said sleeve also compresses the said resilient sealing member toexpand it.
 12. A rock breaker according to claim 10 wherein the saidsleeve extends between the said threaded member and the said collet andhas an expanded portion at the said collet and has the other endexternally threaded and the said resilient sealing member encircles thesaid sleeve and engages the said expanded portion, and by a furthersleeve encircling the first said sleeve to extend between the saidresilient sealing member and a threaded member engaged on the saidthread on the first said sleeve whereby the said threaded member whenmoved toward the said resilient sealing member compresses the saidresilient sealing member to expand it independently of movement of thefirst said sleeve.